A cubic semisymmetric graph is a graph that is both cubic (i.e., regular of vertex degree 3) and semisymmetric (i.e., edge-transitive but not vertex-transitive).
The four smallest cubic semisymmetric graphs are illustrated above. The smallest of these is Gray graph on 54 vertices, the next smallest is the Iofinova-Ivanov graph on 110 vertices (Iofinova and Ivanov 2002, Marušič et al. 2005), the third is the Ljubljana graph (Conder et al. 2002), and the fourth is the Tutte 12-cage.
Some cubic semisymmetric graphs are summarized in the following table.
| graph | |
| 54 | Gray graph |
| 110 | 110-Iofinova-Ivanov graph |
| 112 | Ljubljana graph |
| 126 | Tutte 12-cage |
| 182 | 182-Iofinova-Ivanov graph |
| 506 | 506-Iofinova-Ivanov graph |
| 990 | 990-Iofinova-Ivanov graph |